lengthproperties to do I-don't-remember-what (count word lengths and embolden all words longer than N characters, perhaps).
It lacks only one thing: clearly marking what parts of the input text is part of what match paren pair index. My own plan was to make the entire input text visible somewhere in the page, and then style match 0 (all matched text of the regexp) bold, and 1 (first paren), ...all the way through paren N with differently colored
border-bottom:s, at growing
padding-bottomdistances (since a particular character can be part of many matched parens at the same time, and hence have multiple underlines), and appropriate
titleattributes for each such
span, attributing which parens it was a part of.
MochiKit, again, seems like a really pleasant framework to work with; I've got to play with this. Really. This just might be the ideal entrance door to doing it, too.
The half a second delay until things happens is just silly, though; it ought to be more like a tenth or even fiftieth of a second; computers are fast these days, and this feels like it would be an AJAX application running home to a mother server for answers, rather than done fully client side. It's sluggish, and for no good reason, either.